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Coordination Mode Engineering of Ce-Based Frameworks to Tune Photocatalytic Hydrogen Evolution
Shi-Qing Wang1, Zhao-Feng Qiu2, Yu Wu3
1Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
Inorganic Chemistry
|June 17, 2026
Summary
Modulating coordination in cerium metal-organic frameworks (MOFs) with 2,2'-bipyridine-5,5'-dicarboxylate (bpdc) ligands enhances photocatalytic hydrogen production. Uncoordinated bipyridyl units decrease the band gap, boosting efficiency.
Area of Science:
- Materials Science
- Photocatalysis
- Coordination Chemistry
Background:
- The band gap (Eg) of metal-organic frameworks (MOFs) is crucial for photocatalytic reactions.
- Coordination modes and multinuclear metal centers significantly influence MOF properties.
- Optimizing MOFs for efficient photocatalytic hydrogen evolution is an active research area.
Purpose of the Study:
- To synthesize and investigate cerium-based MOFs (Ce-MOFs) with varying coordination modes of the 2,2 -bipyridine-5,5 -dicarboxylate (bpdc) ligand.
- To evaluate the photocatalytic hydrogen evolution performance of these Ce-MOFs.
- To elucidate the relationship between coordination, band gap, and photocatalytic activity.
Main Methods:
- Synthesis of three Ce-MOFs (Ce-1, Ce-2, Ce-3) with full, partial, and noncoordination of the bipyridyl moiety in the bpdc ligand.
- Photocatalytic hydrogen evolution experiments using platinum (Pt) nanoparticles as cocatalysts.
- Density Functional Theory (DFT) calculations to understand electronic structure and charge transfer mechanisms.
Main Results:
- Ce-3, featuring noncoordinated bipyridyl units, exhibited the highest hydrogen evolution rate (12.99 μmol h⁻¹), 3.61 times that of Ce-1.
- Experimental and DFT results confirmed that increased uncoordinated bipyridyl units lead to a smaller band gap (Eg).
- Oxygen and/or carboxylate bridges in multinuclear Ce-centers facilitate efficient ligand-to-metal charge transfer (LMCT).
Conclusions:
- The coordination mode of the bpdc ligand in Ce-MOFs directly impacts their photocatalytic hydrogen evolution performance.
- Engineering the coordination environment, specifically increasing uncoordinated bipyridyl units, is a viable strategy to tune the band gap and enhance photocatalysis.
- Multinuclear Ce-centers and their bridging ligands play a key role in facilitating charge transfer for improved photocatalytic activity.
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